1. Field of the Invention
The present invention relates to a symbol display device for a game machine, mounted in game machines such as a slot machine and a Pachinko game machine.
2. Background Arts
For game machines such as a slot machine and a Pachinko game machine, it is popular to mount symbol display devices in the game machines recently. In the slot machine, for example, the symbol display device is controlled to start moving symbols with displaying them when a start button is pressed or a start lever is operated after coins are inserted. Then, when a stop button is operated or after a predetermined duration, the symbols are stopped and displayed. Whether the win or the loss and a type of the win are judged from a combination of the symbols displayed on a prize-winning line. If it is judged to generate the win, dividend coins are dispensed.
There are symbol display devices of mechanical reel type and an electronic display type such as a liquid crystal display. In the symbol display device of mechanical reel type, a plurality of reels, provided with a plurality of symbols on the peripheries thereof, are disposed horizontally. Each reel is rotated by a motor for displaying the symbols through a display window provided in front of the reels. When the reels are stopped from rotating, whether the win or the loss is judged from the combination of displayed symbols. In order to improve visibility for the symbols stopped behind the display window of symbol display device of mechanical reel type, light-emitting devices are provided inside the reels to illuminate the symbols from behind of them.
Since the number of symbols to be provided on a single reel is limited in the symbol display device of mechanical reel type, it is difficult to provide a variety of contents for a game. In order to deal with this problem, a variety of symbol display devices having reel units composed of outer reels and inner reels rotating within the outer reels have been disclosed.
For example, Japanese Patent Laid-Open Publication Number 2002-126229 discloses a double drum (reel assembly) composed of an inner drum (reel) and an outer drum (reel), which are rotated by individual driving motors, having symbols on the peripheries thereof. Since the inner drum and the outer drum have the same symbols thereon and the symbols on the outer drum are formed to be either transparent or translucent, the symbols on the inner drum are observable through the symbols on the outer drum. Thus the symbols on the inner drum and on the outer drum overlap with each other to appear in three dimensions. In addition, light-emitting devices are provided inside the inner drums to illuminate the symbols on both the inner drums and the outer drums from their behind in order to improve the visibility for the symbols.
Such a symbol display device, however, has the following problems: first, the visibility for the symbols become deteriorated when the light-emitting devices inside the inner drums are lit up, for the shapes and the colors of the symbols on the inner drums are reflected on the symbols on the outer drums. Secondly, the game does not have diversified contents even with the double drum, since the double drum may not have more kinds of symbols than a single drum, as the symbols on the inner drum and on the outer drum are identical. Furthermore, as the light-emitting devices have no light guiding means, the light from the light-emitting devices may not be efficiently guided to the symbols so as to clearly display the symbols.